Small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA)

The protein contains 313 amino acids for an estimated molecular weight of 34063 Da.

 

Co-chaperone that binds misfolded and hydrophobic patches-containing client proteins in the cytosol. Mediates their targeting to the endoplasmic reticulum but also regulates their sorting to the proteasome when targeting fails (PubMed:28104892). Functions in tail-anchored/type II transmembrane proteins membrane insertion constituting with ASNA1 and the BAG6 complex a targeting module (PubMed:28104892). Functions upstream of the BAG6 complex and ASNA1, binding more rapidly the transmembrane domain of newly synthesized proteins (PubMed:28104892, PubMed:25535373). It is also involved in the regulation of the endoplasmic reticulum-associated misfolded protein catabolic process via its interaction with BAG6: collaborates with the BAG6 complex to maintain hydrophobic substrates in non-ubiquitinated states (PubMed:23129660, PubMed:25179605). Competes with RNF126 for interaction with BAG6, preventing the ubiquitination of client proteins associated with the BAG6 complex (PubMed:27193484). Binds directly to HSC70 and HSP70 and regulates their ATPase activity (PubMed:18759457).', '(Microbial infection) In case of infection by polyomavirus, involved in the virus endoplasmic reticulum membrane penetration and infection via interaction with DNAJB12, DNAJB14 and HSPA8/Hsc70 (PubMed:24675744). (updated: June 20, 2018)

Protein identification was indicated in the following studies:

  1. Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
  2. Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
  3. Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
  4. Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
  5. D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
  6. Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.

Methods

The following articles were analysed to gather the proteome content of erythrocytes.

The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.

PublicationIdentification 1Uniprot mapping 2Not mapped /
Obsolete		TrEMBLSwiss-Prot
Goodman (2013)2289 (gene list)227853205992269
Lange (2014)123412347281224
Hegedus (2015)2638262202352387
Wilson (2016)165815281702911068
d'Alessandro (2017)18261817201815
Bryk (2017)20902060101081942
Chu (2018)18531804553621387

1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry

The compilation of older studies can be retrieved from the Red Blood Cell Collection database.

The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.

No sequence conservation computed yet.
Protein sequence (FASTA)
Protein coevolution profile (FreeContact)
Multiple Sequence Alignment (Muscle)

Interpro domains
Total structural coverage: 42%
Model score: 25
MODL_I-TASSER-3.0

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The reference OMIM entry for this protein is 603419

Small glutamine-rich tetratricopeptide repeat-containing protein, alpha; sgta
Small glutamine-rich tetratricopeptide repeat-containing protein; sgt

CLONING

The SGT protein interacts with the parvovirus nonstructural protein NS1. Kordes et al. (1998) used yeast 2-hybrid screening to isolate a human SGT cDNA from a placenta library. The SGT gene encodes a 313-amino acid polypeptide containing 3 tetratricopeptide repeat (TPR) protein-protein interaction motifs. Northern blot analysis revealed SGT expression as a 2.4-kb mRNA at comparable levels in all human tissues tested.

GENE FUNCTION

Tobaben et al. (2001) showed that rat Csp (DNAJC5; 611203) interacted with Sgt and Hsc70 (HSPA8; 600816) in a complex located on the synaptic vesicle surface. The complex functioned as an ATP-dependent chaperone that reactivated a denatured substrate. Sgt overexpression in cultured rat hippocampal neurons inhibited neurotransmitter release, suggesting that the Csp/Sgt/Hsc70 complex is important for maintenance of a normal synapse.

MAPPING

Kordes et al. (1998) used fluorescence in situ hybridization to map the SGTA gene to human chromosome 19p13. ... More on the omim web site

Subscribe to this protein entry history

July 2, 2018: Protein entry updated
Automatic update: Entry updated from uniprot information.

Feb. 10, 2018: Protein entry updated
Automatic update: Entry updated from uniprot information.

Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated

Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated

March 16, 2016: Protein entry updated
Automatic update: OMIM entry 603419 was added.

Jan. 25, 2016: Protein entry updated
Automatic update: model status changed